Spotting and centering drills with indexable replaceable inserts are used to form spotting and centering holes in a workpiece. These holes provide an accurate center position for twist, spade or other drills used to drill a straight, deep bore in the workpiece. One such drill is described in U.S. Pat. No. 5,259,707 to Keller ("the '707 patent"). The cutting insert of the tool described in the '707 patent features a V-shaped cutting edge. The two sides of the cutting blade are symmetrical, with the apex of the "V" disposed coaxial with the axis of rotation of the drill. This design is problematic because at the center of rotation no cutting forces are applied. Instead, workpiece material at the axis of rotation is pressed aside by the point of the insert, which increases cutting forces and temperature of the tool, decreases tool life and, in some cases, decreases feed rates.
Indexable drills featuring a shank and multiple cutting inserts, with the point of the insert being radially offset from the rotational axis, are known in the art. Such a drill is described in U.S. Pat. No. 5,758,997 to Mealey et al. ("the '997 patent"). FIG. 9 of the '997 patent suggests it is known to radially offset the point of a cutting insert relative to the rotational centerline of the tool. The cutting tool of the '997 patent is principally intended to drill holes, typically using a spotting hole for a guide. Because of the use of even numbers of inserts to balance drilling forces, and the relatively shallow cutting angles of the inserts of the drill of the '997, it is apparent the drill is not designed to form spotting or centering holes.